1. Field of the Invention
The present invention relates to a venturi burner for pulverized coal, and a novel burner for burning pulverized coal in a furnace in a manner which minimizes the formation of oxides of nitrogen in the burning process.
2. Description of the Prior Art
A wide variety of burner designs have been developed over the years and some of the burners used in furnaces, boilers and the like have been especially suited for burning pulverized coal. One of the major problems in burning pulverized coal as well as other fossil fuels is the production of oxides of nitrogen in the combustion process. Many attempts at burner design have been directed toward reducing the amount of oxides of nitrogen that are formed. Such oxides, known as NOX cause air pollution and are generally objectionable.
A number of articles and reports have been published concerning oxides of nitrogen including burner designs and methods of reducing and controlling the formation of "NO.sub.x ", and are listed as follows:
(1) Lim, K. J., Milligan, R. J., Lips, H. I., Castaldini, C., Merrill, R. S. and Mason, H. B., "Technology Assessment Report for Industrial Boiler Applications: NO.sub.x Combustion Modification," Acurex Corporation for Environmental Protection Agency, EPA-600/7-79-178f, Research Triangle Park, NC, December, 1979. PA0 (2) & (4) Heap, M. P., Lowes, T. M., Walmsley, R., Bartelds, H. and LeVaguerese, P., "Burner Criteria for NO.sub.x Control, Volume 1, Influence of Burner Variables on NO.sub.x in Pulverized Coal Flames," International Flame Research Foundation, EPA-600/2-76-061a, March, 1976. PA0 (3) Brown, R. A., Mason, H. B., Schreiber, R. J., "Systems Analysis Requirements for Nitrogen Oxide Control of Stationary Sources." NTIS-PB-237-367, EPA-650/2-74-091, September, 1974. PA0 (5) Information presented at the Third Technical Panel Meeting, "EPA Low NO.sub.x Burner Technology and Fuels Characterization," Newport Beach, CA, November, 1979. PA0 (6) Beer, J. M., and Chigier, N. A., "Combustion Aerodynamics" Applied Science Publishers, 1972. PA0 (7) DyKema, O. W., "Analysis of Test Data for NO.sub.x Control in Coal Fired Utility Boilers," Aerospace Corporation for Environmental Protection Agency, EPA 600/2-76-274 (NTIS No. PB 261 066,) Research Triangle Park, NC, October, 1976. PA0 (8) Martin, G. B. and Bowen J. S., "NO.sub.x Control Overview, International Symposium on NO.sub.x Reduction in Industrial Boilers, Heaters and Furnaces," Houston, TX, Oct. 22-23, 1979. PA0 (9) Rawdon, A. H. and Johnson, S. A. "Application of NO.sub.x Control Technology to Power Boilers," Proceedings of the American Power Conference, Vol. 35, pp. 828-837, 1973. PA0 (10) Rawdon, A. H., Lisauskas, R. A., Zone, F. J., "Design and Operation of Coal-Fired Turbo.RTM. Furnaces for NO.sub.x Control," presented at the Second EPRI NO.sub.x Technology Seminar, Denver, CO, November, 1978. PA0 (11) Brown, R. A., "Alternate Fuels and Low NO.sub.x Tangential Burner Development Program," proceedings of the Third Stationary Source Combustion Symposium Volume II, Advanced Processes and Special Topics, Acurex Corporation for Environmental Protection Agency, EPA-600/7-79-0506, Research Triangle Park, NC, February 1979. PA0 (12) Zeldovich, J., "Acta Physicochimica U.R.S.S.," Volume 21, No. 4, 577, 1946. PA0 (13) Pershing, D. W., Brown, J. W., Martin, G. B. Berkau, E. E., "Influence of Design Variables on the Production of Thermal and Fuel NO.sub.x from Residual Oil and Coal Combustion," presented at the 66th Annual AICHE Meeting, Philadelphia, PA, November, 1973.
The following U.S. patents are directed towards burners for furnaces and the like which employ pulverized coal or other hydrocarbon fossil fuels as a source of energy for combustion:
______________________________________ 246,321 Litchfield et al 3,007,084 Thomasian et al 1,342,135 Schmidt 3,150,710 Miller 1,817,911 Andrews et al 3,450,504 Korwin 1,953,090 Vroom 4,019,851 Smith et al 1,993,901 Silley 4,089,628 Blackburn 2,158,521 Nahigyan 4,147,116 Graybill 2,325,318 Hendrix 4,157,889 Bonnel 2,823,628 Poole et al 4,228,747 Smirlock et al ______________________________________